A highly accurate numerical model was developed for modeling the transport of heavy metals in estuaries. The methodology uses measurements of dissolved and particulate fractions of metals, and associated salinities to develop partitioning coefficients as a function of salinity. These relationships were incorporated into high resolution numerical models to simulate the transport of metals about the Mersey Estuary. For most of the metals the approach worked very well; however, the transport of Hg was not well simulated. The paper discusses the form of the partitioning coefficient-salinity relationships with other research in this field and makes suggestions for future research. (C) 2011 Civil-Comp Ltd and Elsevier Ltd. All rights reserved.